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Sustainable Energy Generation by Bio Fuel Cell from Septic Tank

Published on Nov 30, 2023


Non convention energy generation is one of the important social needs. Our country investing huge money on that for solar energy and wind energy. Lot of research is in progress to utilise waste material. The sewage from the residential building generates methane gas by microorganism in the sludge. So far the septic tanks are constructed in the residential building for collection and draining of effluent from the residence. The effluent collection at the septic tank is containing organic matter those are consumed by micro-organism and are generating hydrogen ion and other gases in an anaerobic and aerobic condition. It is proposed to utilise a septic tank into a power generation unit by incorporating stack of bio fuel cell driven by micro-organism. The bio fuel cell is designed by the concept of H+ ions in the anaerobic condition reacting with oxygen in aerobic condition to form water through proton exchange membrane. This process drives electron from anode to cathode is tapped. The generated power is regulated and the constant power supply is obtained which is useful for residential purpose. A prototype cell was fabricated and tested by polarization. It is found that the voltage gain is 0.59 V. The power generation Design an electrolyte for anaerobic and aerobic condition.

Keywords : Sustainable energy, Biofuel cell, electrodes and voltage stabilizer.


 Design electrode system for microbial fuel cell.

 To regulate output current for household utility.

 To design a suitable septic tank system found to be varying that depends upon the quantum of microorganism.


 Non metallic Cell

 Electrodes

 Electrolytes

 Proton exchange membrane

 Booster

 Regulator

Non-metallic cell:

The non-metallic cell was fabricated by using PVC pipe, elbow, flange, proton exchange membrane etc. It has a capacity of 150 ml on each side.


Carbon fibre was reported in the literature to be an ideal electrode for microbial fuel cell. Accordingly Carbon fibre was used as electrode both for anodic and cathodic sides to generate power. Initially the cell was generated 0.33 V. Further the literature collection advocates to use copper as cathode so that the benefit of galvanic effect may also be drawn. Then copper mesh electrode was introduced so that the surface area can be increased. As the surface area increases the microorganisms reactions will increase which results in better power generation


In Anodic chamber sewage added with yeast was filled. In cathodic chamber the distilled water is added with KMnO4 solution for better mobilization of ions

Proton exchange membrane:

At initial stage the RO membrane was tried and later the Nafion membrane-117 was introduced for better performance. The Nafion member is considered an attention as a proton conductor for proton exchange membrane (PEM) fuel cells because of its excellent thermal and mechanical stability.


The voltage that is directly coming out from the Microbial fuel cell is very low which will limit its application. So, in order to use the cell in large scale with variety of application we have to boost the voltage coming out from the Microbial fuel cell which is done by a Voltage booster.


A voltage regulator is a voltage stabilizer that is designed to automatically stabilize a constant voltage level. A voltage regulator circuit is also used to change or stabilize the voltage level according to the necessity of the circuit.

Detail of work carried out:

a) Fabrication of prototype cell

b) Stack of eight cell

a. Aerobic and anaerobic condition

b. Reducing the distance between the electrodes

c) Fabrication of prototype cell

The above figure is showing a prototype cell. Fabrication of prototype cell has done by using flange, elbow, PVC pipe, and ion exchange membrane and carbon fibre.

 The cell contains two compartments. The left compartment of the cell contains sewage whereas in right compartment contains normal water with 0.1 N KCl.

 The ion exchange membrane is place in between the compartments.

 The carbon fibre kept in both sides which acts as anode and cathode.

2. Stack of eight cells:

The proto type cells are fabricated having capacity of 150ml in each compartment. Both compartments are separated by “nafion-117” (membrane). Anaerobic condition was created in anode side. Yeast was added in the anaerobic compartment. This mixture is placed in a sealed chamber to create anaerobic condition thus forcing the micro-organism to undertake anaerobic respiration. Eight numbers of such cells were fabricated and connected by series. From those cells the desired voltage and current was obtained that can boost and regulate easily.

Results and Discussions

Sustainable Energy


 Extensive use of natural fuel sources demanding researchers to device an alternative renewable energy generation methods. Moreover, using of fossil fuels may cause environmental pollution. Clean fuels such as fuel cells and bio-fuels are the new sources of energy without any pollution. They are the suitable replacements of traditional fossil fuels

 Microbial fuel cells are individual kinds of Fuel Cells which use active biocatalysts such as micro-organisms or enzymes to generate energy. Microbial fuel cells are one of the newest techniques in that the hydrogen ion from anaerobic condition reduces with oxygen at aerobic condition produce electrons that are taped as renewable energy.

 Carbon fibres are proved better as anode for Microbial fuel cells.

 Introducing copper mesh will yield higher energy due to the combined effect of microbial activity and galvanic effect.

 Microbial fuel cells can be the best alternative to minimize the pollution and to utilize the waste sewage to generate power for the residence.

Project Done By Ms. Yogashree G, Mr. Vivek Kumar, Mr. Sanesh Regmi, Ms. Shalinee Singh